4-Output Video Interface for MBP?

[ovrarrest]

Hi Fred. I've decided to give this route a try: 4 USB to VGA adapters + 2 Mini DisplayPort to RCA adapters. If this ends up not working well, I will have to try a more expensive set-up.

Do you know if there is there a brand of USB adapters that are particularly fast on Macs? And do you think using USB 3.0 adapters instead of USB 2.0 adapters will result in a significantly better playback response? I ask because the USB 2.0 adapters can be found used for cheaper, while the USB 3.0 adapters I would have to buy new.

[Marci]

Re: TH2Go DP vs Digital SE

_Basically..._

TH2Go DP is 1x DP in, 3x DP out.

TH2Go Digital SE is 1x DP in, 3x DVI out.

_Delving deeper into it for getting 6 outputs (running two matching units on same firmware)..._

TH2Go DP can be doubled up, one on each Thunderbolt port, to give 2x triple output groups via mGXM.

Digital SE can't. See output table yonder (bottom of page): http://www.matrox.com/graphics/en/products/gxm/connect_multiple_gxms/

[Marci]

PS: Long term, you may be better off purchasing a ViDock (http://www.villagetronic.com/g4/expansion/shop) and suitable graphics card (which doesn't need to be anything massively meaty, just summat with enough outputs for you). I'd consider this the midway option between USB adapters and adding dedicated players to each screen. Probably doable for the cost of a pair of TH2Go or less.

[ovrarrest]

Hi Marci. On the Matrox webpage you linked to, it says, "Multiple GXMs are supported under Windows only." So whether I use a DP or Digital SE, I can only use one TH2Go with my MBP at a time.

Also, the ViDock looks like a great solution. However, it looks like each ViDock can support 2 graphics cards per Thunderbolt output, so I could get 4 outputs from my MBP at the maximum? I would be paying several hundreds of dollars for only 2 extra outputs then.

[Fred]

@Marci do these work with gfx cards on OSX? As far as I have heard there are no solutions for this on a rmbp (external video card) they work fine for other peripheral cards, but maybe things have changed since I last checked.

@[ovrarrest](http://troikatronix.com/troikatronixforum/profile/6179/ovrarrest) where did you find mini display port to composite video? As far as I knew the displayport standard (mini display port is the same thing with a smaller plug) does not support this. 

As for the better performance in USB2 vs 3 it does not really work like that. When you plug in USB devices they use a subset of the controller which is limited to USB 2, when you use USB 3 devices it uses the USB 3 controller. The speed issue I mentioned was for hubs not controllers. You are still in unchartered territory trying to use 4 of these. If I am correct about the mini display port not having composite you still need to convert from VGA or HDMI to composite (also dont forget your macbook retina also has a dedicated HDMI). On the plus side, many of these USB adaptors do support multiple monitors on windows - you could run your patch on windows installed on your mbp. Here is a working setup that would be close to what you want https://www.youtube.com/watch?v=pYUdAWOGJ_Y

[ovrarrest]

@Fred Here are some Mini DisplayPort to RCA (composite) converters I referenced earlier:

http://www.amazon.com/DisplayPort-Composite-Video-S-Video-Converter/dp/B004VV8R86

http://www.amazon.com/J-Tech-Digital-Mini-DisplayPort-Converter/dp/B008CS0J9O

http://www.amazon.com/ViewHD-DisplayPort-Thunderbolt-Universal-Converter/dp/B00713AA5E/

Isn't USB 3.0 faster than USB 2.0 though? That's why I might have thought USB 3.0 could handle 4 adapters better than USB 2.0 could?

Yeah I've thought about running Windows on my Mac as there are many videos online with people using their Windows computers with multiple displays. I view this as a last resort since I'm not really comfortable in Windows.

My rMBP has 2 Thunderbolt outs and 1 HDMI out, but keep in mind the computer only allows me to use a total of 2 of these outputs simultaneously.

I do think the ViDock would work on Max OSX. From their [FAQ page](http://www.villagetronic.com/g4/expansion/products/nano/faq):

_"Compatibility of ViDock to Mac OS_

_Apple and Intel officially do not support external GPU. This is why getting external GPU to work on Mac OS can be rough. Once it works, it works great. Instead Windows 7 / 8 support external GPU and the experience is great right from the start. This holds still true when running Windows OS on Mac hardware._

_Back to ViDock on Mac OS:_

_- You need to use a GPU that has drivers built-into MacOS_

_- Better to choose a Mac that has no discrete graphics"_

So it seems it is possible to use ViDock on Macs.

[Michel]

@ovrarrest

_My rMBP has 2 Thunderbolt outs and 1 HDMI out, but keep in mind the computer only allows me to use a total of 2 of these outputs simultaneously._

I can use all three outputs simultaneously.

Best
Michel

[Fred]

Yes, you can use all three at the same time on the rMBP.

for vidock

_- Better to choose a Mac that has no discrete graphics"_

_And your retina has discrete graphics so it is outside of the advice._

As for the display port stuff, looks like these will be display port to VGA with a cheap scan convertor built in- that is what the USB is for- to power the scan convertor, otherwise composite, and the need for USB power are outside of the display port spec. As you are using old TVs you might not notice the image quality, but generally cheap scan converters don't look so good.

I guess I have a different opinion on setups, for me possible to work is never good enough. My reputation is the reliability of my systems, I need them not to fail and not to be a pain to setup if I am not there. In this way I try to always use tested, supported and professional solutions. In the end if you are comfortable with un tested/unreliable/unsupported systems and can handle the risks then there are a lot more options to work with.

[ovrarrest]

@Michel and @Fred Oh, wow, I didn't realize that the rMBP could output to three external displays simultaneously! Which means I only need 3 USB adapters to get 6 outputs going.

@Fred I understand where you're coming from. What scan converter would you recommend to connect an old TV to a Mini DisplayPort? And do you recommend a specific RF modulator?

[Fred]

It has been a long time since I used composite video but I was using Kramer vp501 I think. But think about what you would use again from the setup. I would look for rental scan convertors instead of buying second rate ones. But maybe the old TVs won't see the difference... It is an even longer time since I used rf so not sure.

[Marci]

@ovrarrest - depends WHICH rMBP you've got. If memory serves, only the ones with nVidia GPU can drive all 3 outputs at once - the regular IRIS only chipset rMBPs can only drive 2. (I could be wrong tho).

Yep, Vidock works on OSX with graphics cards, and their are single graphics cards out there that have up to 6x native outputs built in... therefore you could run 12x with 2 such cards in a ViDock - you just need to hunt further when it comes to the choice of graphics card.